Speaking of wild Book of Mormon theories, I've heard it suggested on this very forum that the Book of Mormon was written by some ancient, white Indians on gold plates in Egyptian characters and hidden in a hill for 1,400 years only to have the ghost of one of these Indians appear to a 17 year old treasure hunter to reveal its secrets. Crazy stuff, I know.

There's more similarity between Kircher's invention and my proposed design than you might think. First of all, we have a glass ball with rotating object(s) suspended inside for both. The exact size really isn't that important since the design is scalable. Inside Kircher's "clock" we have a ball rotating in a horizontal plane with an indicator (in the form of a fish) pointing to numbers on the ball. In my Liahona design we have a spindle inside rotating in the horizontal plane. This spindle is the pointer (but it is definitely not a fish). The other Liahona spindle points to objects on the surface of the ball (similar to how Kircher's pointer points to numbers on an inner ball). In Kircher's clock a mystical force (thought to emanate from the sun) turned the objects inside the ball. The objects inside the Liahona are also rotated by an external, mystical force. It's not hard to see how Kircher's device could have spurred the creation of the Liahona as I have proposed it.

This is an interesting but very limited study. I would be interested in a stylometric analysis of 17th Century authors, particularly Grotius, as compared to the Book of Mormon. Grotius would have presumably been influenced by the literature he was familiar with which was much different than the 19th Century English authors in the study. He was very interested in ancient Greek literature and translated several Greek plays into Latin. He was well-read in a slew of other ancient sources and I imagine he would have been familiar with contemporary European authors, as well.

Start with a glass ball. Inside the ball one spindle stretches from the south pole to the north pole through the center. This spindle spins on its axis. The second spindle is horizontal at the equator and stretches from east to west through the center. It also spins on its axis. The two spindles are connected at the center of the globe forming right angles. Now if we spin the the N/S spindle the E/W spindle rotates in a horizontal plane and becomes a pointer. If we spin the E/W spindle the N/S spindle rotates in a vertical plane and becomes a pointer. Thus they are described both as spindles (1 Nephi 16:28, Alma 37:40) and as pointers (1 Nephi 16:10,28; Alma 37:40,44). One of the spindles points the direction of travel. The second spinner points to an emblem on the surface of the ball indicating what the other spindle is pointing at.

Spindle is the key word. A spindle is round and spins around its axis like a top. Compass pointers are not spindles. For one, they’re likely to be flat. And they rotate radially. Once you make a spindle a spindle it changes the game.

When I talk about “your” design I am specifically referring to the characteristics mentioned in the article you wrote and provided a link to. I hardly think it’s out of line to attribute what you wrote to you.
I am not suggesting the Liahona cannot conceivably be ball-like rather than a perfect sphere. I am suggesting that an actual ball fits the text better than a ball-like object.
It’s true that in modern navigation or surveying (something I have some practical experience doing) you need a basis of bearing and then an offset angle (or azimuth) in order to correctly describe a new bearing. If I were surveying a property boundary I would describe each segment of the polygon with an offset angle, be it from true north or some other bearing. If I were navigating with a map I would find the correct bearing I should be heading by looking at the map and using a protractor or other device to determine my intended azimuth. Then I would set this offset on my compass after correcting for the magnetic declination. In both the surveying and navigation example I would need a “spindle” or other type of pointer to indicate my basis of bearing. The azimuth would be set by me, the operator of the device, based on visual confirmation of property markers in the surveying example or the calculated angle in the navigation example. Thus I would be able to advance in the direction indicated either to measure a distance or to proceed on a route. This new direction is thus totally determined by my actions and calculations. If I understand you correctly, you are saying that the operator would then set the second spindle at the required offset and then travel in that direction as in using a magnetic compass. This would work as long as you had some marker for your first spindle and it was allowed to spin freely so that it always could be allowed to point at magnetic north. The problem I see is that this is not what is being described in the text. I do not see any indication the operator is required to manipulate the device. It seems to work autonomously. And when it refuses to work it seems to do that autonomously, as well. But, as before, I am not rejecting the idea outright. I am simply showing that a different design harmonizes better with the text.
The suggestion I am making is that the spindles are actual spindles, not clock hands. That is, they both rotate axially.
In short I’m saying that when the text says ball it most likely means ball. When it says spindles it most likely means spindles. When it says “if they had faith to believe that God could cause that those spindles should point the way they should go” it most likely means God points the spindles without human manipulation. Combined, I don’t think it’s unfair to say the Liahona was most likely not a magnetic compass.

Your description is actually very helpful and I think I have a design that meets all the criteria including this new information. My design has two spindles whose lengths are essentially the diameter of the inside of the ball. They are attached at their midpoints forming a cross. Each spindle can spin on its axis independently. This allows one of the spindles to point the direction to go while allowing the other spindle to point at the thing they are headed toward. And importantly, these are spindles in the true sense of the word as well as being pointers. But I think it has to be a glass ball instead of a brass ball. This is the only stretch I am making on the text. However, I believe it fits all other descriptions given.

I’m pretty sure I got this merit badge. 😉The second pointer is not necessary. Even a magnetic compass typically only has one. But this isn’t a magnetic compass anyway. The spindle simply points the way to go. A magnetic component to this device is unnecessary.
And I think we need to understand what a spindle is and does. It spins—but not radially. It spins axially. Your design has two clock arms, not two spindles. Nor do I think most of the proposed designs you showed qualify as a ball in the truest sense. I am not coming up with unnecessary impediments. I am simply reading the text for what it says. You are suggesting a ball that is not really a ball and spindles that are not really spindles (one of which provides no useful functionality).

What does it mean that spindles can be set in the top of the ball? If we take the text literally we have a brass globe with two spindles inside the globe. How are these spindles even visible? We either need gaps in the ball’s surface so we can see inside or we need a ball that’s flat or concave on the top to hold our compass spindles. But neither of these precisely fits the description. Maybe you are envisioning a different design. A glass orb allows us to see inside of it.
Another issue is the second spindle. Your proposed second spindle seems superfluous. There’s no need to point to magnetic north or any direction, for that matter. Simply follow the pointer. The sun and stars will indicate the direction of travel. My proposed design provides a useful purpose for the non-pointer spindle. It rotates and allows the pointer spindle to point in any direction.
Plus we have the word “spindle” to deal with. The most common use of the word indicates something round and slender and associated with axial rotation. Your compass design has no axial rotation at all from either spindle.
We also have some ambiguity in the text that I think my design resolves. 1 Nephi 16:28 mentions “pointers” and Alma 37:40 indicates the “spindles should point the way they should go”. The problem is that 1 Nephi 16:10 clearly tells us that only one spindle pointed the way to go. So how is it that these other two verses seem to be telling us that both point the way to go? My answer is that they work together to point the way, the one rotating axially and the other, attached to it, doing the actual pointing. With a compass design the ambiguity is unresolved.

Previously I've shown Galilean thought in the design of the Jaredite barges, the heliocentric description of the universe, and Alma's faith experiment. There are further indications of scientific thought by Galileo and his contemporaries in the design and operation of the Liahona. In the late 1630's a Jesuit priest named Francis Line invented a so-called magnetic clock in an effort to vindicate Galileo who was under house arrest. It was a glass ball resting on a base in which a small sphere was suspended in liquid. The inner sphere rotated slowly, doing a complete revolution in 24 hours, and a pointer in the ball pointed at the revolving sphere to indicate the hour of the day. The explanation for its operation was that a magnetic field from the sun was causing the inner sphere to rotate. This was the same power, according to Line, that caused the earth to rotate. The only problem was that it was all a hoax. There was actually a water clock held in a compartment below the base that turned a magnet causing the suspended ball to turn. A similar clock was re-produced by another Jesuit priest named Athanasius Kircher which is shown below. He had a fish as a pointer and the inner sphere was made of copper or bronze.
When Galileo heard about the clock he guessed the trick behind it, even claiming to have made one himself. Finally in 1641 Kircher revealed the trick in a publication which showed the water clock beneath.
There are a couple of obvious parallels to the Liahona. First is the round shape and second is the use of a pointer inside the ball. This brings up some questions about the ball described in the Book of Mormon. 1 Nephi 16:10 describes "a round ball of curious workmanship; and it was of fine brass. And within the ball were two spindles; and the one pointed the way whither we should go into the wilderness." One question I've always had about this description is how spindles could move or even be visible inside a ball of brass. Is it possible that the word was supposed to be "glass" instead of "brass"? Perhaps it was misheard by the scribe. A glass ball filled with a liquid with two spindles would be quite similar to the magnetic clock. Imagine one spindle running axially through the ball from the south pole to the north pole with the second spindle attached at the midpoint and protruding outward. As the axial spindle rotated the pointer spindle would point the way to go.
Now the other function of the Liahona was providing written instructions from time to time. Curiously, the words would appear and then later be gone. To our 21st Century minds this is no big deal. We are used to screens on which words appear and disappear. But to an ancient mind, words normally appeared in ink or in engravings--in other words--permanently. So appearing and disappearing words would have been quite a novel idea. However, another invention which appeared around the same time could explain the inspiration behind this. The aforementioned Kircher published a book in 1645 describing a primitive projection device called a stenographic mirror. Words or images painted on a concave mirror could be projected onto a surface with a source of light.
A similar invention was produced by a Dutch inventor named Cornelis Drebbel in the early 1620's. The point is that the idea of a projected image was just coming into existence. An image or writing could be made to show up and then disappear, surely a novel idea at the time.
So we have some inventions that occur at precisely the time I've proposed for the production of the Book of Mormon and in precisely the right location that could easily have provided the inspiration behind the Liahona. When you combine this with the other Galilean thought I've identified it makes a pretty good case that the science of the Book of Mormon closely corresponds to the science of Europe in the first half of the 17th Century.

Menasseh ben Israel, who I mentioned earlier, was a known associate of Grotius so I’ve been going through some of his writing, particularly Hope of Israel. One thing he mentions is that he believes Israelites were scattered to China and then made their way to Panama and Peru.
This mirrors Grotius’ idea that the people of Peru came from China. We know from footnote 21 of the paper I linked to that Grotius was considering ben Israel’s hypothesis on Jewish origins when he wrote his dissertation. So perhaps Grotius bought into the Israelite/Chinese/Peruvian connection. If so, he was careful not to mention the Israelite part of it—possibly for the polemical reasons I’ve already mentioned. Interestingly we find Isaiah 49 (cited by ben Israel in support of the Chinese connection) in the Book of Mormon in the context of the scattering and gathering of Israel (1 Neph 19-21). If you connect the dots the Book of Mormon in these chapters is telling the people of Peru (among others) that they are part of the lost tribes and this message is meant for them.

I’m reading Menasseh ben Israel’s Hope of Israel (1652) which basically identifies the lost tribes with many different people around the world including some in America. His comments give us an idea how someone from that time understood the phrase “islands of the sea.”
The point is I don’t think we necessarily have to take the word isle or island literally.